Molecular approaches allow investigators to delineate the mechanisms that implement the normal developmental program of each cell, and pathologic processes that cause development to go awry. This Core has been configured to facilitate implementation of these approaches. It provides investigators with the equipment, materials, and expertise needed to efficiently identify and characterize molecules of interest, and to manipulate the expression of these molecules to ask biologically relevant questions. The core has two major components; Biology Facility, which incorporates a newly established Protein Isolation Unit, and the Mass Spectrometry Facility. Each component provides a key service for analyzing complex molecular mixtures. The Molecular Biology Facility will provide capabilities for and instruct users in polymerase chain reaction (PCR) amplification of nucleic acid sequences, subcloning and amplification of plasmids, analysis of nucleic acids by agarose and acrylamide electrophoresis, Northern and Southern blotting, and DNA sequencing. The facility will serve as a common source for vectors and bacterial strains, and provide pretested competent cells for routine subcloning procedures. Molecular biological reagents such as restriction enzymes, DNA and RNA modifying enzymes, autoradiographic film, polaroid film, and transfection reagents will be obtained at bulk rates. The Protein Isolation Unit offers (a) the capability for employing sophisticated methodology for protein isolation and characterization, and (b) instruction in these techniques. Protein isolation and characterization is often closely related to the nucleic acid work carried out in the Molecular Biology Facility; it is frequently a necessary first step in the cloning of genes that encode proteins of biological importance. The Mass Spectrometry Facility provides investigators with a collaborative research resource that has the expertise and equipment to provide a wide range of mass spectrometry services, including structure determination, measurement of sample components, metabolite profiling and stable isotope tracer studies. Facility personnel have expertise in the analytical chemistry and biochemistry of glycoconjugates, lipids, peptides, bile acids, and amino acids.